Correlations of the time dependent signal and the state of a continuously monitored quantum system

TL;DR

This paper investigates the temporal correlations in signals and quantum states of a continuously monitored superconducting qubit undergoing Rabi oscillations, revealing insights into quantum measurement dynamics.

Contribution

It provides experimental analysis of time-dependent correlations in quantum trajectories under continuous weak measurement, linking observations to quantum measurement theory.

Findings

Identification of significant temporal correlations in measurement signals

Correlation between quantum trajectories and measurement back action

Insights into quantum measurement and photodetection processes

Abstract

In quantum physics, measurements give random results and yield a corresponding random back action on the state of the system subject to measurement. If a quantum system is probed continuously over time, its state evolves along a stochastic quantum trajectory. To investigate the characteristic properties of such dynamics, we perform weak continuous measurements on a superconducting qubit that is driven to undergo Rabi oscillations. From the data we observe a number of striking temporal correlations within the time dependent signals and the quantum trajectories of the qubit, and we discuss their explanation in terms of quantum measurement and photodetection theory.